The present disclosure relates to a developing device and an image forming apparatus provided with the same, and in particular relates to a developing device including a discharge passage where a developer discharge port for discharging developer is formed, and an image forming apparatus provided with the same.
In image forming apparatuses, a latent image formed on an image carrier constituted by a photosensitive member and the like is developed by a developing device to be visualized as a toner image. Examples of the developing device include one employing a two-component developing method in which a two-component developer is used. The developing device of this type includes a developing container, in which a two-component developer including a toner and a carrier is stored, and there are arranged a developing roller that supplies the developer to the image carrier and a stirring member that supplies the developer in the developing container to the developing roller while stirring and conveying the developer.
In the developing device employing the two-component developing method, the toner is consumed through developing operations, while the carrier circulates in the developing device without being consumed, and deteriorates with time. As a result, charging performance of the carrier with respect to the toner is gradually degraded.
As a solution to this problem, there has been known a method for preventing deterioration of the charging performance of the carrier, and such a method is embodied in, for example, a developing device in which deterioration of the charging performance of the carrier is reduced by supplying fresh developer including fresh carrier to a developing container, while discharging surplus developer.